Many consumers receive entertainment programming carried via digital signals. Programming (e.g., television programs, movies, sports events, music, etc.) is encoded at a head-end using a compression standard such as Motion Pictures Experts Group (MPEG) or H.264. The resulting stream of frames is transmitted to a media receiver, which may decode and display the stream, store the stream for later viewing, and/or further process the encoded stream.
The digitally encoded stream is carried over a core network (such as the Internet) downstream to the edge of the network, where the core network interfaces with a subscriber access network. The digitally encoded stream may be transformed or consumed by one or more intermediate processing functions located at the edge. Examples of such intermediate processing functions include network-based digital video recording, video on demand, fast channel change, video error repair, encryption/key generation, and digital program insertion. Some of these intermediate processing functions operate by locating key frames or other “points of interest” within the encoded stream. Conventional solutions place the functionality of locating points of interest within the intermediate processing function. However, locating points of interest is relatively compute-intensive, since this involves examining the structural information in each encoded elementary stream and in the multiplexed transport stream when transport streams are used. When such conventional solutions also encrypt the transport stream and/or the elementary stream, then locating points of interest also requires first decrypting the transport stream packets. Thus, a more flexible technique for locating points of interest, and for communicating this information to intermediate processing functions, is desired.